Wells are generally drilled into subsurface rocks to access fluids, such as hydrocarbons, stored in subterranean formations. The subterranean fluids can be produced from these wells through known techniques. Operators may want to know certain characteristics of produced fluids to facilitate efficient and economic exploration and production. For example, operators may want to know flow rates of produced fluids. These produced fluids are often multiphase fluids (e.g., those having some combination of water, oil, and gas), making measurement of the flow rates more complex.
Various systems can be used to determine flow rates for multiphase fluids. In some systems, multiphase fluids are separated into their constituent phases and these phases are then individually tested to determine flow rates. Separators use gravity to separate gas and liquid components of a multiphase fluid within a separation vessel. Two-phase separators can be used to separate gas from liquid components of the multiphase fluid, and three-phase separators can be used to separate gas, water, and oil. Diffusers, demisters, and other devices can be used within the separation vessel to facilitate separation. The separated fluids can be routed from the separation vessel via outlet lines. Parameters, such as volumetric flow rate, of the separated fluids flowing through the outlet lines can then be determined.